Peter L. Clinco v. Commissioner
US Tax Court · Feb 9, 2026
What happened in this matter?
The U.S. Tax Court admonished counsel for submitting a brief containing multiple fabricated and misrepresented case citations, which the Court attributed to the likely use of generative AI. Although the Court characterized the conduct as unacceptable and a violation of Rule 11(b), it did not impose a formal monetary or professional sanction, opting instead to issue a stern warning.
- Why the court cared
- Fabricated: Case Law | Counsel cited "Cacchillo v. Commissioner, 130 T.C. 132 (2008)" in support of a signature requirement; the Court found no such case at that citation and that the citation appears fabricated. || Misrepresented: Case Law | Counsel cited "Miller v. Commissioner, 57 T.C. 440 (1971)" to support a proposition about notices of deficiency; the Court observed the actual Miller decision cited by counsel is a T.C. Memo. (1984-448) and the reporter page at 57 T.C. 440 is a different case, so the citation was incorrect/misrepresented and did not support counsel's point. || Fabricated: Case Law | Counsel cited "Tefel v. Commissioner, 118 T.C. 324 (2002)" for a signature-formalities proposition; the Court found no case named Tefel at that citation (page 324 of 118 T.C. is Hillman v. Commissioner) and treated the citation as fabricated.
- Why it matters now
- Tax Court reads every citation; fabricated Tax Court cites are instantly caught and attributed to AI.
Why this matter is tracked
In a tax deficiency dispute, the petitioner's counsel submitted a brief containing multiple fabricated case citations, including 'Cacchillo v. Commissioner,' 'Miller v. Commissioner' (incorrectly cited), and 'Tefel v. Commissioner.' The U.S. Tax Court identified these as likely hallucinations generated by a large language model. The Court noted that the citations were nonexistent or misrepresented, violating the duty of candor and Federal Rule of Civil Procedure 11(b). While the Court expressed strong disapproval of the use of AI-generated fictitious caselaw, it stopped short of imposing formal sanctions in this specific instance, noting that the embarrassment of the exposure and the failure to verify were sufficient for the time being. The Court ultimately ruled against the petitioner on the merits of the tax deficiency.
Tax Court reads every citation; fabricated Tax Court cites are instantly caught and attributed to AI.
Record details
What the record establishes about AI use
The Court attributed the citations to a large language model.
Memorandum Findings of Fact and Opinion issued by the U.S. Tax Court following a petition challenging a notice of deficiency.
Correction behavior is not separately verified in the current record.
Tracked discrepancy record
3 citation, quotation, or authority issues are recorded in the source dataset.
- Fabricated: Case Law | Counsel cited "Cacchillo v. Commissioner, 130 T.C. 132 (2008)" in support of a signature requirement; the Court found no such case at that citation and that the citation appears fabricated.
- Misrepresented: Case Law | Counsel cited "Miller v. Commissioner, 57 T.C. 440 (1971)" to support a proposition about notices of deficiency; the Court observed the actual Miller decision cited by counsel is a T.C. Memo. (1984-448) and the reporter page at 57 T.C. 440 is a different case, so the citation was incorrect/misrepresented and did not support counsel's point.
- Fabricated: Case Law | Counsel cited "Tefel v. Commissioner, 118 T.C. 324 (2002)" for a signature-formalities proposition; the Court found no case named Tefel at that citation (page 324 of 118 T.C. is Hillman v. Commissioner) and treated the citation as fabricated.
Questions this record answers
- What happened in Peter L. Clinco v. Commissioner?
- The U.S. Tax Court admonished counsel for submitting a brief containing multiple fabricated and misrepresented case citations, which the Court attributed to the likely use of generative AI. Although the Court characterized the conduct as unacceptable and a violation of Rule 11(b), it did not impose a formal monetary or professional sanction, opting instead to issue a stern warning.
- Why does Peter L. Clinco v. Commissioner matter for legal AI risk?
- Tax Court reads every citation; fabricated Tax Court cites are instantly caught and attributed to AI.
- What does the public record establish about Peter L. Clinco v. Commissioner?
- Retained unchanged after audit: the existing summary is source-specific, non-placeholder, and supported by the recorded source link. Read the underlying source before relying on it for legal advice or a filing.
- Which source supports this Peter L. Clinco v. Commissioner summary?
- The recorded source is Damien Charlotin case archive. It is classified as publisher document archive; review the linked material and subsequent docket history before relying on this summary.
Related matters
Related by court, jurisdiction, tool, or classified failure pattern. Similarity does not imply the same facts or outcome.